1. Field of the Invention
The present invention relates to a method for forming a transparent conductive film on an upper layer of a conductive substrate material.
2. Description of the Related Art
Conventionally, when forming a transparent conductive film, a wiring is initially formed on a transparent substrate, and an interlayer film is formed on this wiring. A contact hole is then formed Into this interlayer film using, for example, dry-etching. It is known that on the substrate material inside the contact hole in the interlayer film, an unnecessary insulating film is formed such as a damage layer developing when, for example, dry-etching and/or a natural oxidation film.
If proceeding with the forming of the transparent conductive film while leaving this unnecessary insulating film as it is, the unnecessary insulating film will have an influence on the electrical properties of the transparent conductive film due to its insulating effect. Therefore, conventionally, such an unnecessary insulating film is attempted to be removed (see for example Japanese Patent Application Laid-Open No. 9-186101 (FIG. 2)). In such conventional art, this unnecessary insulating film developing after forming the contact hole into the interlayer film on the surface of a gate electrode composing the substrate material, consisting for example of aluminum, is removed by wet etching.
As it is, in such conventional art, after forming the contact hole to the gate electrode, the exclusive removal of the unnecessary insulating film has to be carried out by wet etching in a separate manufacturing step from forming the transparent conductive film. This extra step is counterproductive to efforts to simplify manufacturing steps.
Accordingly, the present invention is intended to solve the above-mentioned issue by providing a method for forming a transparent electrode film that allows simplifying the manufacturing steps by omitting the step of exclusively removing the unnecessary insulating film that develops after forming the contact hole.